At present, conductive inks are used for making conductive wirings on a variety of insulating media, in particular on films or sheets of plastics material used for making electronics cards.
Prior to application, such inks include grains of metal, generally grains of silver which has a melting point that is high, which grains are dispersed in an organic material in the liquid phase. While it is being applied, the ink is raised to a temperature that causes the organic material to set, thereby connecting the metal grains together with or without evaporation of a portion of the liquid phase. The application temperature is generally about 70.degree. C.
Because of the high melting temperature of the metal grains, it is very difficult to achieve local melting of the conductive ink in order to bond it with a component after the conductive ink has been deposited, or to interconnect two conductive wirings of different makeups implemented one after the other on a common substrate. A high temperature capable of melting the metal grains would damage the substrate which is generally made of a plastics material having a melting point that is lower than the melting point of the metal grains. Present inks therefore often give rise to electrical connections that are defective even though a wiring made of the conductive ink is physically in contact with a component or with another wiring.